Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the description only needs incremental value. It does add one real behavioral fact: results are filtered to subdivisions that actually have a playable channel, which is not derivable from the annotations or schema. It says nothing about result size, ordering, or nesting.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One short sentence fragment with no filler; the scope qualifier is the only content and it is front-loaded. It is efficient, though arguably under-specified rather than truly concise.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only list tool with full schema coverage and no output schema, the description is minimally viable. It does not clarify the parent/child relationship with list_countries, nore whether the result set is paginated or hierarchical.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the single parameter (country, ISO 3166-1 alpha-2) is documented in the schema itself. The description adds nothing about the filter's semantics or what happens when country is omitted, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the resource (states/provinces) and adds a scope qualifier ('that have a playable channel'), which is more than a tautology. However, it is a bare noun phrase with no verb and it draws no boundary against clearly related siblings such as list_cities, list_countries, or list_networks, which follow the same 'list X' pattern. It is also written in Portuguese while the tool and sibling names are English, adding friction.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no statement of when to use this tool versus list_countries or list_cities, no prerequisites, and no mention of how the country parameter changes the call. Usage must be inferred entirely from the name.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.